Sex-specific differences in neuromuscular activation of the knee stabilizing muscles in adults: a systematic review

Introduction The rupture of the anterior cruciate ligament (ACL) is one of the most common injuries of the knee. Women have a higher injury rate for ACL ruptures than men. Various indicators for this sex-specific difference are controversially discussed. Aim A systematic review of the literature that compares surface electromyography (EMG) values of adult female and male subjects to find out if there is a difference in neuromuscular activation of the knee stabilizing muscles. Methods This systematic review has been guided and informed by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Studies which examined sex-specific differences with surface EMG measurements (integral, root mean squares, mean values, analysis of time and amplitude) of the knee stabilizing muscles were retrieved via searches from the databases PubMed, CINAHL, Embase, CENTRAL and SPORTDiscus. The risk of bias of included studies was assessed with the National Heart, Lung and Blood Institute (NHLBI) study quality assessment tool. A synthesis of results was performed for relevant outcomes. Results Fifteen studies with 462 healthy participants, 233 women (mean age 21.9 (± 2.29) years) and 299 men (mean age 22.6 (± 2.43) years), were included in the systematic review. The methodological quality of the studies was mostly rated “fair” (40%). A significantly higher activity of the muscles vastus lateralis and vastus medialis was found in females, in three studies. Two studies found significantly lower neuromuscular activity in the muscles biceps femoris and semitendinosus in females. All other included studies found no significant differences or reported even contradicting results. Conclusion The controversial findings do not allow for a concluding answer to the question of a sex-specific neuromuscular activation. Further research with higher statistical power and a more homogeneous methodical procedure (tasks and data normalisation) of the included studies may provide insight into possibly existing sex-specific differences in neuromuscular activation. This systematic review could help to improve the methodical design of future studies to get a more valid conclusion of the issue. Trial registration CRD42020189504

Acute effects of stochastic resonance whole body vibration.

AIM: To investigate the acute effects of stochastic resonance whole body vibration (SR-WBV) training to identify possible explanations for preventive effects against musculoskeletal disorders. METHODS: Twenty-three healthy, female students participated in this quasi-experimental pilot study. Acute physiological and psychological effects of SR-WBV training were examined using electromyography of descending trapezius (TD) muscle, heart rate variability (HRV), different skin parameters (temperature, redness and blood flow) and self-report questionnaires. All subjects conducted a sham SR-WBV training at a low intensity (2 Hz with noise level 0) and a verum SR-WBV training at a higher intensity (6 Hz with noise level 4). They were tested before, during and after the training. Conclusions were drawn on the basis of analysis of variance. RESULTS: Twenty-three healthy, female students participated in this study (age = 22.4 ± 2.1 years; body mass index = 21.6 ± 2.2 kg/m2). Muscular activity of the TD and energy expenditure rose during verum SR-WBV compared to baseline and sham SR-WBV (all P < 0.05). Muscular relaxation after verum SR-WBV was higher than at baseline and after sham SR-WBV (all P < 0.05). During verum SR-WBV the levels of HRV were similar to those observed during sham SR-WBV. The same applies for most of the skin characteristics, while microcirculation of the skin of the middle back was higher during verum compared to sham SR-WBV (P < 0.001). Skin redness showed significant changes over the three measurement points only in the middle back area (P = 0.022). There was a significant rise from baseline to verum SR-WBV (0.86 ± 0.25 perfusion units; P = 0.008). The self-reported chronic pain grade indicators of pain, stiffness, well-being, and muscle relaxation showed a mixed pattern across conditions. Muscle and joint stiffness (P = 0.018) and muscular relaxation did significantly change from baseline to different conditions of SR-WBV (P < 0.001). Moreover, muscle relaxation after verum SR-WBV was higher than after sham SR-WBV (P < 0.05). CONCLUSION: Verum SR-WBV stimulated musculoskeletal activity in young healthy individuals while cardiovascular activation was low. Training of musculoskeletal capacity and immediate increase in musculoskeletal relaxation are potential mediators of pain reduction in preventive trials. Key Words: Musculoskeletal system, Electromyography, Quasi-experimental study, Prevention, Relaxation Core tip: Musculoskeletal function improves after application of stochastic whole body vibration (SR-WBV). The pathway of the beneficial effect, however, is unclear. This study shows SR-WBV to increase muscle activity of descending trapezius muscle, the muscle that is often associated with reported pain in computer work. Participants report improved muscular relaxation after SR-WBV while the cardiovascular activation was very low. In addition to ergonomic interventions SR-WBV may help to prevent trapezius muscle related pain at work

Wavelet analyses of electromyographic signals derived from lower extremity muscles while walking or running: A systematic review.

Surface electromyography is often used to assess muscle activity and muscle function. A wavelet approach provides information about the intensity of muscle activity and motor unit recruitment strategies at every time point of the gait cycle. The aim was to review papers that employed wavelet analyses to investigate electromyograms of lower extremity muscles during walking and running. Eleven databases were searched up until June 1st 2017. The composition was based on the PICO model and the PRISMA checklist. First author, year, subject characteristics, intervention, outcome measures & variables, results and wavelet specification were extracted. Eighteen studies included the use of wavelets to investigate electromyograms of lower extremity muscles. Three main topics were discussed: 1.) The capability of the method to correctly assign participants to a specific group (recognition rate) varied between 68.4%-100%. 2.) Patients with ankle osteoarthritis or total knee arthroplasty presented a delayed muscle activation in the early stance phase but a prolonged activation in mid stance. 3.) Atrophic muscles did not contain type II muscle fiber components but more energy in their lower frequencies. The simultaneous information of time, frequency and intensity is of high clinical relevance because it offers valuable information about preand reflex activation behavior on different walking and running speeds as well as spectral changes towards high or low frequencies at every time point of the gait cycle

Anwendung und Optimierung des Schweizer Interprofessionalitäts-Evaluations-Instrumentariums SIPEI

Das Schweizer Interprofessionalitäts-Evaluations-Instrumentarium SIPEI wurde entwickelt, um die in der Praxis umgesetzte interprofessionelle Zusammenarbeit (IPZ) an Institutionen des Gesundheitswesens zu evaluieren. Das Instrumentarium wurde als Teil des Förderprogramms «Interprofessionalität» des Bundesamts für Gesundheit erarbeitet und sollte im Rahmen dieses Projekts erstmalig eingesetzt werden. Ziel des Projekts war es, das Instrumentarium SIPEI durch den Einsatz in verschiedenen Settings auf Validität und Reliabilität zu prüfen. Ferner sollten Möglichkeiten zur Optimierung des Instrumentariums aufgezeigt werden

Neuromuscular activity during stair descent in ACL reconstructed patients : A pilot study

Background: The anterior cruciate ligament (ACL) rupture is a severe knee injury. Altered kinematics and kinetics in ACL reconstructed (ACL-R) patients compared to healthy participants (ACL-I) are known and attributed to an altered sensorimotor control. However, studies on neuromuscular control often lack homogeneous patient cohorts. The objective was to examine neuromuscular activity during stair descent in patients one year after ACL reconstruction. Method: Neuromuscular activity of vastus medialis (VM) and lateralis (VL), biceps femoris (BF) and semitendinosus (ST) was recorded by electromyography in 10 ACL-R (age: 26 ± 10 years; height: 175 ± 6 cm; mass: 75 ± 14 kg) and 10 healthy matched controls (age: 31 ± 7 years; height: 175 ± 7 cm; mass: 68 ± 10 kg). A 10-minute walking treadmill warm-up was used for submaximal normalization. Afterwards participants descended 10 times a six-step stairway at a self-selected speed. The movement was separated into pre-activation (PRE), weight acceptance (WA) and push-off phase (PO). Normalized root mean squares for each muscle, limb and movement phase were calculated. Kruskal-Wallis ANOVA compared ACL-R injured and contralateral leg and the ACL-I leg (α = 0.05). Results: Significant increased normalised activity in ST during WA in ACL-R injured leg compared to ACL-I and during PO in VL in the ACL-R contralateral leg compared to ACL-I. Decreased activity was shown in VM in ACL-R injured compared to contralateral leg (p b 0.05). Conclusion: Altered neuromuscular activations are present one year after ACL reconstruction compared to the contralateral and healthy matched control limb. Current standard rehabilitation programs may not be able to fully restore sensorimotor control and demand further investigations

Alterations in sensorimotor function after ACL reconstruction during active joint position sense testing. A systematic review.

Abstract Background The anterior cruciate ligament (ACL) rupture can lead to impaired knee function. Reconstruction decreases the mechanical instability but might not have an impact on sensorimotor alterations. Objective Evaluation of the sensorimotor function measured with the active joint position sense (JPS) test in anterior cruciate ligament (ACL) reconstructed patients compared to the contralateral side and a healthy control group. Methods The databases MEDLINE, CINAHL, EMBASE, PEDro, Cochrane Library and SPORTDiscus were systematically searched from origin until April 2020. Studies published in English, German, French, Spanish or Italian language were included. Evaluation of the sensorimotor performance was restricted to the active joint position sense test in ACL reconstructed participants or healthy controls. The Preferred Items for Systematic Reviews and Meta-Analyses guidelines were followed. Study quality was evaluated using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Data was descriptively synthesized. Results Ten studies were included after application of the selective criteria. Higher angular deviation, reaching significant difference (p < 0.001) in one study, was shown up to three months after surgery in the affected limb. Six months post-operative significantly less error (p < 0.01) was found in the reconstructed leg compared to the contralateral side and healthy controls. One or more years after ACL reconstruction significant differences were inconsistent along the studies Conclusions Altered sensorimotor function was present after ACL reconstruction. Due to inconsistencies and small magnitudes, clinical relevance might be questionable. JPS testing can be performed in acute injured persons and prospective studies could enhance knowledge of sensorimotor function throughout the rehabilitative processes

Effekt eines Rumpfkräftigungsprogramms (inklusive Unterarm- und seitlichem Unterarmstütz) auf die Verletzungsrate von erwachsenen Fußballspielern: eine systematische Literaturübersicht

Hintergrund  Fußball gilt als hochintensive Sportart mit einer erhöhten Verletzungsrate. Erwachsene Männer zeigen dabei die größte Verletzungsrate. Aktuell stellt die Kräftigung des Rumpfes einen wichtigen Bestandteil verschiedener Präventionsprogramme dar, wie beispielsweise beim „FIFA 11 +“. Das Ziel dieser Übersichtsarbeit bestand darin, herauszufinden, welchen Effekt ein Rumpfkrafttraining, mindestens bestehend aus den bekannten und einfach durchzuführenden Übungen Unterarmstütz und seitlicher Unterarmstütz, auf die Verletzungsrate bei erwachsenen Fußballspielern hat. Probanden, Material und Methoden  Die systematische Literatursuche erfolgte in den Datenbanken PubMed, PEDro, Cochrane Library, SPORTDiscus und Cinahl. Die Interventionsgruppe musste ein Training der Rumpfmuskulatur (als Teil eines Präventionsprogramms) bei erwachsenen Fußballspielern beinhalten, die Kontrollgruppe ihre gewohnten Trainingseinheiten weiterführen. Der Unterarmstütz wie auch der seitliche Unterarmstütz mussten in der Interventionsgruppe angewendet werden. Als Outcome wurde die Anzahl von Verletzungen und/oder die Verletzungshäufigkeit (pro 1000 h Training und Match) definiert. Die Qualität der Studien wurde mittels der PEDro-Skala und des Risk-of-Bias-Tool beurteilt. Ergebnisse  Total wurden sieben Studien mit insgesamt 2491 Probanden eingeschlossen. In drei Studien fand eine signifikante Abnahme der Verletzungsrate in der Interventionsgruppe statt (p  0,05). Schlussfolgerung  Die sieben Forschungsarbeiten unterschieden sich stark in Bezug auf die Methodik, die Intervention und die Ergebnisse. Zudem wurde der Rumpf nie isoliert, sondern immer als Teil eines Programmes mit weiteren präventiven Maßnahmen, trainiert. Dadurch war ein Vergleich der Studien schwierig. Trotzdem waren Tendenzen zu erkennen, dass sich ein Präventionsprogramm mit Übungen zur Kräftigung der Rumpfmuskulatur positiv auf die Verletzungsrate auswirkt. Aufgrund der aktuellen Studienlage kann die Fragestellung jedoch nicht abschließend beantwortet werden. Es bedarf weiterer Studien, die den Effekt eines isolierten Rumpfkrafttrainings auf die Verletzungsrate bei Fußballspielern untersuchen

The effect of kinesio tape on neuromuscular activity of peroneus longus.

Background: Functional ankle instability is the result of sensorimotor or structural deficits. The commonly used kinesio tape (KT) is supposed to have a positive influence on sensorimotor functions. Methods: Eight women and two men (mean ± SD, age 24.4 ± 3.3 years) with functional ankle instability with recurrent ankle sprains ran downhill on a treadmill (3.3 m/s and a negative slope of 5°). The first trial was without KT, the second with KT on the peroneus longus (PL) muscle. Neuromuscular activity was measured using surface electromyography for 15 seconds. Sensation of giving way was assessed with a visual analog scale (VAS). Comparisons were made between measurements with and without KT using the Wilcoxon rank sum test. The level of significance was set at P ≤ 0.05. Results: None of the chosen parameters for preactivation, reflex activation, or total activation showed statistically significant differences between the two trials (P > 0.05). The mean values for the sensation of giving way were lower with KT (VAS, median 1.2, range 0–2.8) than without (VAS, median 1.8, range 0–3.9), but did not reach statistical significance (P = 0.102) or clinical relevance. Conclusion: KT in participants with functional ankle instability (FAI) seems to have no effect on the neuromuscular activity of PL and sensation of giving way during downhill running

Neuromuscular control in patients with acute ACL injury during stair ascent : A pilot study

Background: Studies showed altered kinematics and kinetics in anterior cruciate ligament (ACL) deficient participants, attributed to an altered sensorimotor control. However, literature on neuromuscular activity during stair ascent in patients with acute ACL rupture. Material and methods: The activity of the M. vastus medialis (VM) and lateralis (VL), M. biceps femoris (BF) and M. semitendinosus (ST) was recorded using surface electromyography (EMG) in 9 acute ACL deficient (ACL-D) (rupture 1-3 weeks prior to test) and 9 ACL intact (ACL-I) matched subjects. Participants ascended 20 times a 6-step stair at self-selected speed. The movement was divided into pre-activation (PRE), weight-acceptance (WA) and push-off (PO) phase. Comparisons were made between the deficient leg of ACL-D and the matched uninjured leg of the ACL-I, as well as between the injured and non-injured leg of the ACL-D group. Results: ACL-D showed in all muscles a reduced activation (ca. 50%, p < 0.05) compared to ACL-I during PRE. In ACLD, quadriceps activity was also reduced (ca. 50%; p < 0.05) during WA, and hamstrings displayed a lower activation (ca. 35%; p < 0.05) during PO. Intragroup comparisons showed less consistent differences in all muscles and phases. Conclusions: Altered activity during PRE indicates an alteration in the motor program (‘‘pre-programmed activity’’). Small differences in the intra-individual comparison showed bilateral consequences following ACL injury. Level of Evidence: